Second virial coefficients of argon, krypton and methane and their binary mixtures at low temperatures

Abstract

A differential method is described for measuring the second virial coefficient of a gas from approximately the normal boiling-point of the substance to room temperature, given the value of the virial coefficient at one temperature. The imperfection of the gas is compared directly with that of a reference gas (helium) for which the second virial coefficient is known over the whole temperature range. Measurements have been made on argon, krypton, and methane, and on a sample, approximately equimolar, of each of the three binary mixtures which can be formed from these gases. The results for the pure gases have been used to demonstrate the superiority of the 18-6 form of the Lennard-Jones potential over the 12-6 form in accounting for low-temperature virial coefficients, while the figures obtained for the mixtures have been applied to examine the validity of three combining rules for estimating the intermolecular energy parameters for a pair of unlike molecules from the corresponding parameters for the two pairs of identical molecules.

Comparison of experimental dilute gas properties with the predictions of three realistic intermolecular potentials for Ar-Kr

“…The latter is the second virial coefficient of a hypothetical pure gas whose molecules interact according to the force law between the components 1 and 2. The data for BI~ have been reported by Fender and Halsey, Jr. [19] (105-123 K, error + 2 per cent), Byrne et al [20] (116-253 K, error + 1 cm3/mole) and Brewer [21] (148-323 K, error + 0.1 per cent). The data have been presented by the original workers, duly corrected for adsorption effects at low temperatures.…”

“…We have re-evaluated the second virials including the first two quantum corrections for all three potentials. The differences between experimental and predicted interaction virial coefficients, AB, for all three potentials are plotted in figure 1 [20] either in testing or adjusting the parameters of their potential functions. If these data are indeed suspect, then they would have an undesirable effect on the adjustment of the parameters.…”

Excluded volume contribution to deviations from ideality in liquid mixtures: Consequences for engineering models

“…For S1 and S2, values for B 12 were found in Refs. [36] and [30], respectively. In the case of S3, B 11 was taken from [30] and a parametrization of B 22 vs. T was found in Ref.…”

Comparison of Lorentz–Berthelot and Tang–Toennies Mixing Rules Using an Isotropic Temperature-Dependent Potential Applied to the Thermophysical Properties of Binary Gas Mixtures of CH4, CF4, SF6, and C(CH3)4with Ar, Kr, and Xe

“…Kalfoglou and Miller (1967) [17] 6 (B) Altogether we put into the minimization procedure 305 experimentally measured values of B, β, and η from 37 sources. for Ar, 210 from 30 sources [14,16,18,26,27,31, for Kr, and 167 from 24 sources for Xe [24,26,27,39,41,49,50,53,54,58,[63][64][65][66][67][68][69][70][71][72][73][74][75]. The obtained LJ (n − 6) potential parameters and the root-mean-square deviations RMS = √ F /M of the "best" solutions are shown in Table I.…”